The invention relates to a liquid crystal cell which functions as a display, whereby a housing thereof contains a support which is configured as a reflector and a heating device for the display.
This type of liquid crystal display is already known in the state of the art (DE 44 17 990 A1) for which a light box is arranged behind a liquid crystal cell, said light box being bordered at its reverse side by a conductor plate which has lights. Between the lights and the liquid crystal cell is located a heating wire, so that the liquid crystal cell can be heated if temperatures are too low.
Further state of the art is a liquid crystal display whose liquid crystal cell has a transparent thin layer heating unit (DE 41 40 415 A1).
Both known liquid crystal displays have in common that high construction expenditures are required in order to assure that the liquid crystal cell is also heated at low temperatures.
The most proximate state of the art is a liquid crystal display with a liquid crystal cell functioning as display, as well as a support configured as a support and a heating device for the display (U.S. Pat. No. 4,643,525). Said heating device is constructed relatively complicated and costly.
In addition, a display device is known (EP-A-0 15 360) for which a heating device is arranged in the cell space of the liquid crystal cell, directly or indirectly on the anterior and/or the posterior cell wall, whereby, likewise, significant construction expense is required for mounting said heating device.
Accordingly, the present invention is based on the object of creating a liquid crystal cell functioning as display, whereby said cell can be heated, even at low temperatures, with low constructional expense.
Said object is solved according to one specific embodiment of the invention is that the heating device is a metallic layer applied directly onto the support and that the metallic layer is produced by coating the support made of plastic with a bonding layer, namely a primer, and by subsequent galvanic coating.
Alternatively, for solving said object, there exists the possibility that for manufacturing the metallic layer it is possible to undertake coating a foil with a bonding layer with subsequent galvanic coating, as well as deep-drawing and rear-spraying of the foil. The metallic layer hereby beneficially serves as resistance heating. By means of this type of metallic layer, which is applied directly onto the support, no additional components need to be mounted.
In order to provide the support with the metallic layer, it is possible to employ the following methods:
1. Coating of the support functioning as reflector with a bonding layer (primer) and with subsequent galvanic coating,
2. Coating of a foil with a bonding layer (primer) and subsequent galvanic coating, deep-drawing of the foil and subsequent rear-spraying of the foil in the support,
3. Manufacturing of the support from a metallizable and a non-metallizable plastic, with subsequent partial chemical metallization of the support. The manufacture of the support from the two kinds of plastic can be done for example by two-component extrusion method.
4. Radiation of a plastic component with a short-wave, ultra-violet light of an Excimer lamp or an Excimer Laser; immersion of the radiated plastic in a watery solution with subsequent additional baths. The layers applied in this fashion can be electrically contacted and galvanically reinforced to thickness customary for conductor tracks.
The galvanic coating with respect to the first-named of the second method can consist, for example, of copper.
In further embodiment of the invention, contacting can be effected either by means of pins injected into the support, preferably made of metal, or directly via metallized plastic surfaces, which are soldered together with the conductor plate.
In further embodiment of the invention, there exists the possibility that the housing and the support equipped with the metallic layer as heating device are designed as a single piece, which results in substantial simplification in the design and reduction in costs.